The U.S. throws away 40% of all the food it grows, so there’s plenty of food waste to go around. At the moment, most of this rotten surplus ends up in landfills, where it produces unwanted gases and takes up space. Might there be a better use for it in making fertilizer?
Several states, like California, are considering laws requiring big producers of organic waste to dispose of it separately, so it doesn’t clog up the main waste stream. Most of this organic waste is likely to go to anaerobic digesters, which convert food into methane, and sometimes into electricity. But Dan Morash, founder of California Safe Soil, argues that the organic matter would be better used to make fertilizer. We already have plenty of natural gas from fracking, he says, and the price is pretty cheap.
There are several ways we might improve fertilizer. For one, much of the nitrogen, potassium, and phosphorous that farmers spread on crops isn’t actually absorbed by the plants. Instead, it gets washed away with the rain and ends up in waterways, where it produces excess algae and kills fish. Fertilizers are also still a significant cost for farmers (though prices have been falling recently).
Morash’s business takes waste from supermarkets in California and turns it into a liquid farmers can use in their drip-lines. The idea is to improve the quality of the soil, and in turn stimulate root growth. That allows the plants to take up more water and fertilizer, and reduces the requirement for both. Morash says farmers can cut their conventional fertilizer inputs by half.
California Safe Soil has been trialling its process for the last two years at a plant in Sacramento. It involves breaking down food in three ways: by mechanically churning it, by using enzymes, and by heating it to a high temperature. In effect, the product, called H2H, is a glorified compost–except it takes just three hours to make, and the result flows into a vat.
Morash says the average supermarket throws away 600 pounds of food a day, of which 70% to 80% is fruits and vegetables. California Safe Soil currently collects from five chains in the state, and recently signed up its first paying customer. The contract with Save Mart, which operates 225 stores, will allow it to set up a larger facility later this year. Morash says supermarkets pay anywhere from $25 to $100 a ton to dispose of the waste today. California Safe Soil charges about half as much.
As for farmers, Morash says several top-25 names in California are signed on to test the product.